GUT MICROBIOME vs your Hormones, Stress and Mood

Suddenly being mentioned everywhere, your ‘gut’ is something you may have heard referred to. It’s the nickname given to your gut microbiome, a community of microorganisms which live in your Gastrointestinal (GI) tract (and also in the tract of every animal). For the most part, the microbiota and your gut live in relative harmony. The gut has a bi-directional relationship (two way communication) with our central nervous system (CNS), this is referred to as the ‘gut-brain axis’. This gut brain axis allows the gut, specifically the microbiota, to send and receive signals to and from the brain.

Some signs and symptoms of an unhealthy gut include:

· Regular cravings for sugar and carbs

· Stomach disturbances such as gas, bloating, irregular toilet habits

· Unintentional weight changes (either up or down)

· Sleep disturbances and fatigue

· Skin issues such as acne or eczema

· Food intolerances

· Autoimmune conditions

· Headaches, brain fog, memory issues

· Poor immune system

It is important to note, due to a variety of factors, including, but not limited to, diet, environment, season, and health status it is virtually impossible to pin down one response to what is a ‘normal’ microbiome for the average human. Gut microbiome can also vary due to genetic diversity, however the dominant species generally results from the composition of a person’s diet (Clapp et al. 2017).

HORMONES

Healthy gut function has been linked to normal CNS function. This in turn means that you’ll have more stability with your sex hormones, thyroid function, and even adrenaline function. Recent studies suggest that the gut-brain axis extends also to the neural, endocrine, and immune pathways (Carabotti et al. 2015).

Both internal hormones and exogenous hormones (those from external sources) affect the body, and the gut. Oestrogen also has a gut biome access, resulting in our gut health altering our hormonal health. β-glucuronidase (an enzyme that breaks apart oestrogen into it’s active forms) is produced by the gut to influence oestrogen regulation throughout the body. This process can be disrupted when the gut is not performing at it’s best, resulting in reduced diversity in the gut microbiota, and then a decline in the amount of active oestrogen that can be used in the body.

“Estrogens are primarily produced in the ovaries, adrenal glands, and adipose tissue and circulate in the bloodstream in free or protein-bound form and first undergo metabolism in the liver, where estrogens and their metabolites are conjugated. Conjugated estrogens are eliminated from the body by metabolic conversion to water-soluble molecules, which are excreted in urine or in bile into the feces. The conjugated estrogens excreted in the bile can be deconjugated by bacterial species in the gut with beta-glucuronidase activity (constituents of the ‘estrobolome’), subsequently leading to estrogen reabsorption into the circulation. Circulating estrogens exert effects on target tissues including breast, which stimulate cellular growth and proliferation. By modulating the enterohepatic circulation of estrogens, the estrobolome affects both the excretion and circulation of estrogens. In turn, the composition of the estrobolome can be shaped by factors such as antibiotics, other drugs, and diet that modulate its functional activity.”Cell Host Microbe. 2011;10(4):324-335.

Oestrogen

The gut microbiome manipulates oestrogen metabolism, and therefore can alter how much oestrogen gets excreted once used, or how much gets re-circulated through the body. Some gut bacteria produce an enzyme called beta-glucuronidase (BG for short), and the more BG which is produced, the less oestrogen is excreted from the body and the more is recirculated (Maryann et al., 2016). Oestrogen is great for female hormonal health, healthy skin and a functioning reproductive system, but too much oestrogen can lead to decreased sex drive, irregular menstrual cycles, frequent headaches, weight gain, and increased PMS symptoms. Greater reabsorption of free oestrogens can also increase the risk of oestrogen-driven cancers such as breast cancer, ovarian, and endometrial cancers.

Strong links have also been made between the gut microbiome and thyroid function, these can include:

· Disruption in iodine uptake;

· Alterations to thyroid-hormone receptors; and

· The liver’s reduced ability to convert T3 and T4 (resulting in a ‘sluggish’ thyroid).

There are currently studies underway looking into the relationship between gut microbiota diversity and autoimmune thyroid disease (AITD), which includes Hashimoto's thyroiditis (HT) and Grave's disease (GD).

Mental Health

GI homeostasis (overall gut health) is imperative to our general health and wellbeing (Lyte, 2010). Recently, studies have shown that variations in the gut microbiome and the effect these have on various central nervous system (CNS) disorders, including (but by no means limited to) depressive disorders, anxiety, schizophrenia, and autism (Mayer et al., 2014). Your gut microbiota are capable of delivering neuroactive substances such as GABA and serotonin, which interact with the gut-brain axis. Current research suggests that certain strands of probiotics can have anti-depressant and anxiety-relieving properties (Evrensel and Ceylan, 2015).

The gut-brain axis pathway. Image created by Megan Clapp and Emily Wilen.

In a double-blind placebo-controlled and randomised parallel group study by Messaoudi et al in 2011 researchers used healthy volunteers who took either Lactobacillus helveticusR0052 and Bifidobacterium longum or placebo for 30 consecutive days. A variety of parameters were tested using the Hopkins symptom checklist, hospital anxiety and depression scale, the perceived stress scale and coping checklist. The results from these tests showed that self-perceived psychological stress levels, as well as tested urinary free cortisol levels were both reduced in the subjects who took probiotics regularly. This means those who were on the frequent probiotics ended up with test results that showed less stress, and less depressed moods.

In summary

There is so much more down the rabbit hole of microbiota which I am currently researching, but I felt the connection to oestrogen metabolism, thyroid health and mental health were the most prevalent. Clearly the relationship between our physical and mental health and gut microbiome is a complex one, where much research still needs to be done. However in saying this, even the current amount of research which has been brought to light reinstates the fact that we need to look after our gut, so you may be wondering, how exactly do we do this?

Some events which can cause changes in our gut microbiome:

· Poor, unvaried diet

· Low fibre diet

· High amounts of artificial sweeteners and/or refined sugars in diet

· Recent course of antibiotics

· Have been on heavy medications (such as during cancer treatment) or other immune suppressant medications (such as those used to treat Crohn’s, rheumatoid arthritis, lupus, or even psoriasis).

As you can see, there’s many lifestyle factors (not just diet-based factors) which can alter the balance of your gut microbiome. Let’s take a look at some adjustments you can make to repair or maintain the integrity of your gut.

1. Eat more prebiotic foods

Foods rich in prebiotic fibres (which help ‘feed’ the good guys in your gut) include leeks, onions, asparagus, rolled oats, bananas, nuts. I personally like to include the addition of a supplement called Gut Performance. Disclaimer: this is not sponsored (nothing on this blog is ever sponsored and no free product is ever received as part of my commitment to only offer unbiased information and genuine product feedback), I do not have an affiliation with the company, it’s just a genuinely great product I have found, and have yet to see something work as effectively for my gut.

2. Consume more probiotics.

Probiotics increase the abundance of good gut bacteria. Keep an eye out for fermented foods, including traditional Greek yoghurt, kefir, kimchi, and sauerkraut.

3. Stress reduction.

4. Sleep properly

Never underestimate the power of consistently good sleep. Train your body to sleep and wake up at similar times each day, remove digital distractions before bed, and make getting AT LEAST 7 hours a priority, 8 is better.

5. Basic healthy eating patterns

Your diet needs to focus on wholesome foods, variety and quality. Alter what fresh produce you consume based on what’s in and out of season to get a diverse range of micronutrients, and consider exactly what it is that’s making up your macros, not all foods are created equal.

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